Drought stress is one of the growing concerns in agriculture management around the world. Adopting tolerant plants to drought conditions could be an appropriate approach to this problem. Bunium persicum is one of the most important medicinal plants of Iran and Turkey as well as neighbouring countries and has been forced into endangered plant status due to mismanagement of its wild habitats. An experiment was conducted in order to evaluate drought tolerance of Bunium persicum and the effects of drought on its essential oil qualitative properties. Two separate plans based on randomised complete block design were performed with 4 drought levels (irrigation after 60, 90, 120, and 150 mm of evaporation from an evaporation basin) and 3 replications. Drought treatments were applied after the stem elongation and flowering stages. Results indicated that applied drought treatments reduced yield and yield components of plants in both growth stages. Some differences were observed in yield components when plants were exposed to drought stress at different growth stages. The essential oil percentage of Bunium persicum was affected by drought conditions, and it was elevated along with increasing drought levels. Due to reduced seed yield, essential oil yield was significantly decreased. Antioxidative activity assessment of seed extracts revealed that drought had positive effects on antioxidant parameters, including 2′-diphenyl 1-picrylhydrazyl radical scavenging activity, hydrogen peroxide scavenging activity, and Fe-reducing power. Phenol content was also improved through applied drought treatments. In general, these results showed the high tolerance of Bunium persicum to drought and also revealed positive effects of drought on the antioxidative activities of plant seeds.

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